import java.util.Scanner;

public class Test {
    public static int search(int[] array,int n){
        int low = 0;
        int high = array.length - 1;
        int mid = low + (high - low) / 2;
        while(low <= high) {
            if(n > array[mid]) {
                low = mid + 1;
            } else if(n < array[mid]) {
                high = mid - 1;
            } else {
                return mid;
            }
            mid = low + (high - low) / 2;
        }
        return -1;
    }
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int n = sc.nextInt();
        int[] array = new int[100];//简单有序数组的二分查找
        for (int i = 0; i < 100; i++) {
            array[i] = i + 1;
        }
        System.out.println("你要查找的数位于数组的第" + search(array,n) + "位");
    }
}
